Bicycle Control Apparatus Delaying Drive Assistance Force Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bicycles with drive assistance electric motors experience inadequate riding comfort due to gaps in drive assistance force when the pedal is at top or bottom dead center, leading to insufficient support and periodic reductions in assistance.
Innovation Solution
A bicycle control apparatus that includes a manual drive force detector and a controller, which delays the reduction in drive assistance force relative to manual drive force reductions, using a shift state detector to adjust the delay based on gear ratio or cadence, ensuring a base drive assistance force is maintained or exceeded during pedal reduction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If drive assistance force is generated in accordance with manual drive force, then the drive assistance force corresponds to the rider's input, but drive assistance force is not generated when pedal is at top dead center or bottom dead center, leading to insufficient support and periodic gaps in assistance
Solution Approach 1:
The controller performs preliminary action by maintaining drive assistance force at a previous level for a predetermined time period after detecting a reduction in manual drive force. This anticipatory maintenance of force prevents the periodic gaps that would otherwise occur at dead centers, ensuring continuous support throughout the pedal rotation cycle.
Solution Approach 2:
The system applies beforehand cushioning by preparing to maintain drive assistance force before the rider experiences the drop. When manual drive force reduction is detected, the controller proactively sustains the previous assistance level for a predetermined duration, cushioning the rider against the upcoming periodic gap in support.
2Speed
If drive assistance force is reduced immediately when manual drive force is reduced, then the control response is fast and accurate, but periodic gaps in drive assistance force occur at dead centers, reducing riding comfort
Solution Approach 1:
The controller implements preliminary action by introducing a predetermined time delay before reducing drive assistance force. This delay allows the assistance to persist through the dead center positions where manual drive force naturally drops, preventing periodic gaps while still responding to sustained reductions in rider input.
Solution Approach 2:
The system applies dynamics by making the drive assistance force reduction conditional and time-dependent rather than immediate. The controller dynamically adjusts the assistance force based on the duration of manual drive force reduction, maintaining force for a predetermined time before implementing reduction, thereby smoothing out periodic variations.
3Ease of operation
If a predetermined time period is introduced to maintain drive assistance force, then periodic gaps in assistance are reduced, but the control system complexity increases
Solution Approach 1:
The controller applies parameter changes by introducing a time-based parameter (predetermined time period) into the control logic. This simple temporal parameter allows the system to maintain drive assistance force through dead center positions without requiring complex mechanical modifications or additional sensors, achieving smoother assistance with minimal added complexity.
Data Source
AI summary
A bicycle control apparatus is basically provided for controlling a bicycle having a drive assistance electric motor. The bicycle control apparatus includes a manual drive force detector, a shift state detector and a controller. The manual drive force detector detects a manual drive force. The shift state detector detects a shift state of the bicycle. The controller issues a command for controlling a drive assistance force to be outputted by the drive assistance electric motor in accordance with the manual drive force detected by the manual drive force detector. The controller controls the drive assistance force to delay a reduction in the drive assistance force in relation to a reduction in the manual drive force upon determining the manual drive force is reduced, and controls the delay in the reduction of the drive assistance force in accordance with the shift state of the bicycle.